Writing instrument



FIG. 1 illustrates a front, bottom and right side perspective view of a writing instrument showing my new design, with the writing tip in the retracted position;

FIG. 2 illustrates a front, top and left side perspective view thereof;

FIG. 3 illustrates a bottom end view thereof;

FIG. 4 illustrates top end view thereof;

FIG. 5 illustrates a front elevation view thereof;

FIG. 6 illustrates a side elevation view thereof;

FIG. 7 illustrates a rear elevation view thereof; and,

FIG. 8 illustrates a rear elevation view of the writing instrument with the writing tip in the extended position. 

The ornamental design for a writing instrument, as shown and described. 